1. Field of the Invention
One embodiment of the present invention relates to an object, a method, or a manufacturing method. In addition, the present invention relates to a process, a machine, manufacture, or a composition of matter. In particular, one embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a driving method thereof, or a manufacturing method thereof. Further, one embodiment of the present invention relates to a heterocyclic compound and a novel method for synthesizing the heterocyclic compound. In addition, one embodiment of the present invention relates to a light-emitting element, a light-emitting device, an electronic device, and a lighting device that include the heterocyclic compound. Note that one embodiment of the present invention is not limited to the above technical field. Specific examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a power storage device, a memory device, an imaging device, a method for driving any of them, and a method for manufacturing any of them.
2. Description of the Related Art
A light-emitting element using an organic compound as a luminous body, which has features such as thinness, lightness, high-speed response, and DC drive at low voltage, is expected to be applied to a next-generation flat panel display. A display device in which light-emitting elements are arranged in matrix is, in particular, considered to have advantages in a wide viewing angle and excellent visibility over a conventional liquid crystal display device.
It is said that the light emission mechanism of a light-emitting element is as follows: when a voltage is applied between a pair of electrodes with an EL layer including a luminous body provided therebetween, electrons injected from the cathode and holes injected from the anode recombine in the light emission center of the EL layer to form molecular excitons, and energy is released and light is emitted when the molecular excitons relax to the ground state. A singlet excited state and a triplet excited state are known as excited states, and it is thought that light emission can be achieved through either of the excited states.
An organic compound is mainly used in an EL layer in such a light-emitting element and greatly affects an improvement in the characteristics of the light-emitting element. For this reason, a variety of novel organic compounds have been developed (e.g., Patent Documents 1 and 2).